Ugh…
We have, yet again, another passenger who knows little between right and wrong. Granted, clipping your nails in public isn’t illegal, but it definitely should be, especially when you’re stuck in a cabin with hundreds of strangers. If you’re going to clip your nails, go to the restroom. And make it quick. People have to go, you know!
But this person did their nail maintenance routine right at their seat for everyone to see. The OP probably saw a little too much. A nail clipping went airborne and landed in someone’s drink! The OP definitely should’ve reported the incident to the owner of the cup, just to stir things up.